1. Technical Field
The present disclosure relates to the safe operation of at least one LED and to monitoring the junction temperature of an LED.
2. Description of the Related Art
Light emitting diodes (LEDs) have a design maximum operating junction temperature. For example, 150 degrees Celsius. Exceeding the maximum temperature reduces lifetime, light output and sudden damage of the LEDs can occur. Furthermore the efficiency of the LEDs is lower with higher temperatures and there is a small color shift of the emitted light. The temperature therefore should be monitored.
Although mounted close to LEDs, an external temperature sensor measurement will always be significantly different from the true junction temperature because it is impossible to place the sensor within a minimum space to an LED simply because of mechanical placing problems. Furthermore the thermal interfacing materials in between the sensor and an LED will create another temperature difference due to the thermal resistance of the materials when transporting the thermal power from the LED junction to the heat sink.